How to change --node-cidr-mask-size= from 24 to 16 or 8

Hello,

To change the --node-cidr-mask-size for your Kubernetes cluster, you’ll need to edit the kube-controller-manager configuration. This configuration file is typically located at /etc/kubernetes/manifests/kube-controller-manager.yaml on the master node.

In the file find the line --node-cidr-mask-size=24 and change it to whatever you need, save the file and exit. The changes should take effect immediately, as the kubelet service automatically restarts the kube-controller-manager pod when it detects changes to the configuration file.

Please note:

• Changing the --node-cidr-mask-size will affect how IP addresses are allocated to nodes and pods in your cluster. Make sure you understand the implications of this change before you make it. For example, if you set --node-cidr-mask-size to 16, each node in your cluster could be assigned up to 65,536 (2^16) IP addresses for its pods. This could quickly use up the IP addresses in your --cluster-cidr range if you have many nodes.

• This change won’t affect any existing nodes in your cluster. It will only affect new nodes that you add after making the change. If you want the change to apply to existing nodes, you’ll need to drain and delete the nodes, then add them back to the cluster.

• If you’re using a network plugin like Calico or Weave, you’ll also need to make sure that your network plugin is configured to handle the new CIDR mask size.